<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
    <script>
       
        const  arr = [
   { 'id': '29', 'pid': '',     'name': '总裁办' },
   { 'id': '2c', 'pid': '',     'name': '财务部' },
   { 'id': '2d', 'pid': '2c', 'name': '财务核算部'},
   { 'id': '2f', 'pid': '2c', 'name': '薪资管理部'},
    { 'id': 'd2', 'pid': '',     'name': '技术部'},
   { 'id': 'd3', 'pid': 'd2', 'name': 'Java研发部'}
 ]

 function tranDataToTree(arr){
       const map={}
       const ass=[]
 arr.forEach((item)=>{
    if(!item.children){

        item.children = []
    }


    map[item.id]=item
 })
    arr.forEach((item)=>{
       const add=map[item.pid]
       if(add){
        add.children.push(item)
       }else{
        ass.push(item)
       }
    })
 console.log(arr);
 console.log(map);
 console.log(ass);

 return ass
}


tranDataToTree(arr)
console.log(tranDataToTree(arr));

    </script>
</body>
</html>